Magnetic Observatory


Site of the Magnetic Observatory. Photograph by Chris Hawkins

The Magnetic Observatory was the site of a remote campus of the Royal Observatory between 1898 and 1959. It was located just south-west of Queen Elizabeth’s Bower and surrounded by a ring of Mediterranean oak trees.

The Royal Observatory provided navigational data required by the government, and in 1816 it was tasked with ensuring that the true north used in maps could be properly aligned to the magnetic north shown by a compass. A building with a tall mast was constructed at the Observatory to record the earth’s magnetic field, but as the number of metal and electrical objects around it increased, its measurements became less reliable. The Observatory sought a new location, and by 1898 one had been acquired in the park 300 metres to the east. 

Initially containing the Magnetic Pavilion, it was officially named the Christie Enclosure after William Christie, the Astronomer Royal of the time, and consisted of several buildings within a square wooden boundary fence of 60 by 60 metres. The introduction of electric trams on the Woolwich Road in 1911 was problematic, but the electrification of the railway line in 1926 meant that, yet again, there was too much magnetic interference. The equipment was moved out of London that year. 

The Christie Enclosure was reused to house some new, modern telescopes as the main Observatory was full. These telescopes were taken to Herstmonceux in Sussex after the Observatory moved there in 1946, but in 1959, the enclosure was returned to the park. The site was cleared, leaving just a fire hydrant cover at the centre and a square of evergreen holm oaks and Turkey oaks around what had once been the site’s perimeter.

An exciting community archaeology project in May 2022 explored what remains of this intriguing site. Local community groups were invited to take part in a number of projects led by Community Archaeologist, Andrew Mayfield. Read the dig diary here.